From an Outside Magazine online article:
In the spring and summer, he trained two to four hours a day, six days a week, running daily and carrying 60 pounds of water up a 4,000-foot peak near his home in Seattle twice a week. “All the research has shown that 80 percent of training for alpine ascents needs to be long duration and low intensity, to build a huge foundation of endurance,” Swenson says. “There are no shortcuts to this. There’s no thirty-minute-a-day gym workout. You have to have the discipline to put the time in.”
As an older climber, when I go out and train on any particular day, my big goal is to not get injured. In my twenties and thirties, I would push through a tight muscle or minor pain, but now I just stop. It’s not worth it. The most important thing is to be able to come back tomorrow.”
(Steve) Swenson laments the common scenario for many older people, who often work too much, exercise too little, and find themselves unhealthy during their golden years. “Imagine spending all your years looking forward to retirement and you can’t enjoy it,” Swenson says.